In the field of the satellite communication, for keeping the communication continuous, the satellite antenna should be always aimed at the satellite so as to avoid the signal loss and communication interruption. However, the satellite antenna can be disposed not only in a fixed base on the ground, but also in the vehicles, e.g. the airplanes, ships, cars, etc. Specifically in the moving vehicle, the orientation of the satellite antenna thereon will be changed easily, and thus the communication signal will become weaker. Once the communication signal is too weak to be recognized, the communication between the satellite antenna and the satellite will be broken. Therefore, for keeping the communication between the satellite antenna and the satellite, it is very important to control the satellite antenna to trace the satellite's orientation.
The conventional methods for controlling the satellite antenna to trace the satellite include the manual tracing method, the programmable tracing method, the automatic tracing method and the stepping tracing method, wherein the manual tracing method is unable to be used in the mobile communication. The programmable tracing method, which records the orbit of the satellite and uses a program to trace the satellite's orientation, is usually appropriate for a fixed base station on the ground rather than in a mobile communication. The automatic tracing method is more appropriate for the mobile communication, which is performed by finding the satellite's orientation first, and then combining the stepping tracing method or cooperating with the inertial navigating system, based on the signal magnitude, to trace the satellite,
Moreover, the conventional device for controlling the satellite antenna to trace the satellite uses a driving motor in each axis of the satellite antenna for driving it to trace the satellite's orientation. Therefore, whether the large-angle motion for fast searching or the small-angle motion for positioning tracing both uses the same motor for driving. Generally, the high-speed property of the motor is different from the low-speed property of the motor, i.e. the motor with the high-speed property hardly drives the micro-range motion and the motor with the low-speed property hardly drives the big-range motion. Hence, while the controlling circuit uses the same gain value, the performance thereof is poor.
In order to overcome the drawbacks in the prior art, a two-sectional controlling method and device for the satellite antenna are provided. The particular design in the present invention can not only keep the satellite antenna aiming at the satellite fast and precisely, but also keep a good and continuous communication. Thus, the invention has the utility for the industry.